Friction bolt

Patent metadata

Field	Value
Publication number	US-10837280-B2
Application number	US-201916445733-A
Country	US
Kind code	B2
Filing date	Jun 19, 2019
Priority date	Nov 30, 2015
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

A friction bolt assembly to frictionally engage a bore formed in rock strata. The assembly includes an elongate tube and an expander mechanism acted on by an anchor mechanism via an elongate bar or cable. A retainer mechanism is mounted to act between the bar or cable and the tube to prevent ejection of the bar or cable from the assembly should the bar or cable break.

First claim

What is claimed is:

1. A friction bolt assembly arranged to frictionally engage an internal surface of a bore formed in rock strata, the assembly comprising:
an elongate tube having a leading end and a trailing end;
an expander mechanism located towards or at the leading end of the tube and arranged to apply a radial expansion force to the tube to secure the assembly to the rock strata;
an elongate bar or cable extending longitudinally within the tube and connected at or towards a first end to the expander mechanism;
a retainer mechanism acting between the tube and the bar or cable, the retainer mechanism including a sustainer attached at or towards the trailing end of the tube and an engager, wherein the engager is configured to engage radially the sustainer to prevent ejection of at least a length portion of the bar or cable from the assembly should the bar or cable break; and
an anchor mechanism positioned at or towards the trailing end of the tube, the anchor mechanism including a fixing mountable at or towards a second end of the bar or cable and configured to brace against the trailing end of the tube that by adjustment creates tension in the bar or cable to act on the expander mechanism to create the radial expansion force, wherein at least a part of the fixing projects radially outward beyond the tube or a component attached to an external region of the tube to be braced against the rock strata at a region around an external end of the bore.

2. The assembly as claimed in claim 1 , wherein the fixing includes a nut and a flange extending radially outward beyond the tube, the flange being configured to be braced against the rock strata.

3. The assembly as claimed in claim 2 , wherein the flange and the nut are formed non-integrally, the nut is coupled directly to the bar or cable; and the flange is positioned axially between the nut and the trailing end of the tube.

4. The assembly as claimed in claim 2 , wherein the flange includes an abutment extending radially outward from the tube and having at least a portion facing generally towards the leading end of the tube, the abutment surface being arranged to be engaged by a rock plate to extend radially outward from the flange and to brace against the rock strata at the region around the external end of the bore.

5. The assembly as claimed in claim 4 , wherein a distance by which the flange extends radially outward from the tube is approximately equal to or greater than a distance by which the flange extends radially inward between the tube and the bar or cable.

6. The assembly as claimed in claim 4 , wherein a distance by which the flange extends radially outward from the tube is greater than half a radial thickness of the bar or cable.

7. The assembly as claimed in claim 2 , further comprising a rock plate arranged to abut against and extend radially outward from the flange to brace against the rock strata at the region around the external end of the bore.

8. The assembly as claimed in claim 1 , wherein the retainer mechanism further includes a restrainer positioned radially between the bar and an inner surface of the tube, the engager being configured to engage radially the restrainer and the restrainer is configured to engage radially the sustainer to prevent ejection of the bar or cable from the assembly should the bar or cable break.

9. The assembly as claimed in claim 8 , wherein the restrainer is a collar having a central bore arranged to receive the bar or cable.

10. The assembly as claimed in claim 9 , wherein the restrainer is formed as a single component.

11. The assembly as claimed in claim 9 , wherein the restrainer is formed as a component having two parts, the two parts being divided axially.

12. The assembly as claimed in claim 8 , wherein the restrainer includes a radially inward facing conical or tapered surface arranged to be engaged by the engager.

13. The assembly as claimed in claim 8 , wherein the restrainer includes a notch formed in a radially outward facing surface of the restrainer to receive radially at least a part of the sustainer.

14. The assembly as claimed in claim 8 , wherein the restrainer includes a barb projecting radially outward beyond the tube to engage the sustainer mounted radially externally at the tube.

15. The assembly as claimed in claim 8 , wherein the restrainer is formed as a single component which is split longitudinally to enable the restrainer to radially expand and contract.

16. The assembly as claimed in claim 8 , wherein the engager includes ribs protecting radially outward from the bar or cable.

17. The assembly as claimed in claim 8 , wherein the engager includes a wedge or ferrule attached to the bar or cable.

18. The assembly as claimed in claim 8 , wherein the sustainer includes a tab projecting radially inward from the tube.

19. The assembly as claimed in claim 9 , wherein the sustainer includes a band or ring attached to the tube and engageable radially with at least part of the engager or the restrainer.

20. The assembly as claimed in claim 1 , wherein the tube includes a split extending longitudinally and arranged for radial expansion and contraction.

21. The assembly as claimed in claim 1 , wherein the sustainer includes a bridge tab secured across the split at or towards the trailing end of the tube, the bridge tab having a portion that is bent radially inward to extend within the tube towards the bar of cable.

22. A friction bolt assembly arranged to frictionally engage an internal surface of a bore formed in rock strata, the assembly comprising:
an elongate tube having a leading end and a trailing end;
an expander mechanism located towards or at the leading end of the tube and arranged to apply a radial expansion force to the tube to secure the assembly to the rock strata;
an elongate bar or cable extending longitudinally within the tube and connected at or towards a first end to the expander mechanism;
a retainer mechanism acting between the tube and the bar or cable, the retainer mechanism including a sustainer attached at or towards the trailing end of the tube, the retainer mechanism being configured to prevent ejection of at least a length portion of the bar or cable from the assembly; and
an anchor mechanism positioned at or towards the trailing end of the tube, the anchor mechanism including a fixing mountable at or towards a second end of the bar or cable and configured to brace against the tube such that by adjustment creates tension in the bar or cable to act on the expander mechanism to create the radial expansion force, wherein at least a part of the fixing projects radially outward beyond the tube or a component attached to an external region of the tube to be braced against the rock strata at a region around an external end of the bore.

Assignees

• Sandvik Intellectual Property

Inventors

• Rataj Mieczyslaw
• Young Peter
• Darlington Bradley

Classifications

• E21D21/008

  Anchoring or tensioning means · CPC title

• E21D21/0086

  Bearing plates · CPC title

• E21D21/0026

  characterised by constructional features of the bolts · CPC title

• E21D21/0033

  having a jacket or outer tube · CPC title

• E21D21/006

  Anchoring-bolts made of cables or wires · CPC title